In my U.S. Pat. Nos. 4,519,903 and 4,579,656 there are disclosed various forms of leaf type filtering apparatus especially adapted to filtering, in a relatively compact apparatus, large volumes of liquids to remove contaminant particles from the liquids.
My prior patents disclose apparatus in which a plurality of individual generally rectangular filter leaf assemblies are located in spaced parallel relationship to each other within a tank into which fluid to be filtered is continuously fed. The individual leaf assemblies include a generally rectangular filter media support grid or core formed of intersecting longitudinally extending and transversely extending webs, with the panel being fixedly mounted along one side in the wall of an outlet pipe. A bag-like filter element enshrouds the panel and pipe.
In order that fluid flowing through the filter element into the cell-like grids between the webs of the panels can be conducted to the outlet pipe, it is necessary that flow passages be formed through the individual webs so that the fluid can flow from one cell to the next and eventually be discharged into the outlet pipe.
In the leaf assemblies disclosed in my two above referred to patents, the grid-like panels, as received from their manufacturer, have no openings through their webs. To form these openings, two grid panels as received from the manufacturer are required to form a single filter leaf panel. Slots are cut from one side of each panel into all of the webs and the two panels are then bonded to each other with the slotted sides of the webs in face to face engagement with each other. When so assembled, the slots in the webs define the openings or flow passages between adjacent cells. While the slotting and bonding of the panel is not an especially difficult or complex process it represents a substantial percentage of the cost of the completed panel.
As disclosed in my aforementioned patents, the grid-like panels are fixedly mounted upon their respective outlet pipes by forming a panel receiving slot in the wall of the pipe through which the panel projects. The pipes and panels are formed of a synthetic plastic material which is readily joined by a bonding process, however, the thickness of the panel webs is quite small and in order to achieve an adequate bonding area between the panel and pipe, it was necessary to project the panel edge across the entire interior passage of the pipe so that one longitudinal edge of the panel could be bonded to the inner wall of the pipe. This requirement not only complicates the assembly operation, but also results in an unwanted obstruction to flow through the pipe.
Further, the enclosing or enshrouding of the panel with the filter media requires the performance of at least some sewing and sealing operations on the media after it has been initially positioned on the assembled pipe and panel. The enshrouding requirement restricts the choice of filter media to material which is flexible and capable of being sealingly seamed in place by manually manipulable tools.
The present invention is directed to filter leaf assemblies which overcome the problems referred to above, as well as others.